Ophthalmic Lens With Graded Microlenses

ABSTRACT

An ophthalmic lens incorporating an array of microlenses.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 17/461,780 filed Aug. 30, 2021 entitled OphthalmicLens With Graded Microlenses, which is a continuation of and claimspriority to U.S. patent application Ser. No. 16/503,272 filed Jul. 3,2019 entitled Ophthalmic Lens With Graded Microlenses (now U.S. Pat. No.11,131,869 issued Sep. 28, 2021), which is a continuation of and claimspriority to U.S. patent application Ser. No. 15/130,831 filed Apr. 15,2016 entitled Ophthalmic Lens With Graded Microlenses (now U.S. Pat. No.10,386,654 issued Aug. 20, 2019), which claims benefit of and priorityto U.S. Provisional Application Ser. No. 62/148,102 filed Apr. 15, 2015,entitled Ophthalmic Lens with Graded Microlenses, all of which arehereby incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to ophthalmic lenses and, moreparticularly, to ophthalmic lenses employing one or more arrays ofmicrolenses.

BACKGROUND OF THE INVENTION

In order to refract light, the common denominator in conventionalophthalmic lenses is the difference in curvature between the frontsurface and the back surface. However, this poses certain limitations inthe design of certain high-end lenses such as prescription sunglassesand progressive lenses. In the case of prescription sunglasses, suchdesign limitations result in prescription sunglasses typically onlybeing available in a limited range of prescriptions. The choice of thecurvature of the front surface of the lens (base curve) is determined bythe geometry of the frame that wraps around the face. Most prescriptionsunglasses must, therefore, be made using base curves in the range ofsix to eight diopters. As a consequence, prescription sunglasses forwearers with a high degree of ametropia would present extremely thickedges in the case of high of myopes, or extremely thick centers in thecase of high hyperopes. For this reason, prescription sunglasses aremost commonly available for the population whose prescription is in therange of about minus three diopters to plus three diopters.

In the case of multifocal lenses, for example progressive additionlenses, PALs, such design limitations result in only small portions ofthe progressive addition lens being functional for different lenspowers. The geometry of the continuous progressive surface makes itimpossible for the lens designer to design lenses with large, wide, andclear regions all at once. Likewise, a design with a larger near regionwill have a narrower distance region and a design with a shortercorridor to fit a small frame will have more astigmatism, and so on.

Hence, there exists a need for ophthalmic lenses, lens designs, andmethods for manufacturing ophthalmic lenses that provide relatively thinprescription clear lenses and sunglasses manufactured for any desiredprescription. There also exists a need for ophthalmic lenses, lensdesigns, and methods for manufacturing ophthalmic lenses that providefor multifocal lenses that have relatively large optically functionalportions for the different lens powers.

SUMMARY OF THE INVENTION

The present invention provides ophthalmic lenses, lens designs, andmethods for manufacturing ophthalmic lenses that achieve relatively thinprescription sunglasses manufactured for any desired prescription. Thepresent invention also provides ophthalmic lenses, lens designs, andmethods for manufacturing ophthalmic lenses that achieve multifocallenses that have relatively large optically functional portions for thedifferent lens powers. These objectives are achieved, in part, byproviding an ophthalmic lens comprising: a base lens substrate having afront optical surface and a back optical surface; and an array ofmicrolenses incorporated into at least a portion of the base lenssubstrate.

These objectives are achieved, in part, by a multifocal ophthalmic lenscomprising: a base lens substrate having a front optical surface and aback optical surface; and an array of microlenses incorporated into atleast a portion of the base lens substrate, the array of microlensescomprising a first plurality of microlenses having a first optical powerand a second plurality of microlenses having a second optical powerdifferent from the first optical power.

These objectives are achieved, in part, by a method for forming anophthalmic lens comprising: obtaining a base lens substrate; andincorporating an array of microlenses across at least a portion of thebase lens substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of which embodiments ofthe invention are capable of will be apparent and elucidated from thefollowing description of embodiments of the present invention, referencebeing made to the accompanying drawings, in which

FIG. 1 is a partial perspective view of a microlens array according toone embodiment of the present invention.

FIG. 2 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 3 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 5 is a cross-sectional view of a portion of a lens employing amicrolens array according to one embodiment of the present invention.

FIG. 6 is a cross-sectional view of a portion of a lens employing amicrolens array according to one embodiment of the present invention.

FIG. 7 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 8 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 9 is a plan view of a portion of a microlens array according to oneembodiment of the present invention.

FIG. 10 is a plan view of a portion of a microlens array according toone embodiment of the present invention.

FIG. 11 is a plan view of a portion of a microlens array according toone embodiment of the present invention.

FIG. 12 is a plan view of a lens employing a microlens array accordingto one embodiment of the present invention.

FIG. 13 is a plan view of a lens employing a microlens array accordingto one embodiment of the present invention.

FIG. 14 is a comparison of cross-sectional views of a typical ophthalmiclens and a lens employing a microlens array according to one embodimentof the present invention.

FIG. 15 is a perspective view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 16 is a comparison of cross-sectional views of a typical ophthalmiclens and a lens employing a microlens array according to one embodimentof the present invention.

FIG. 17 is a perspective view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 18 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 19 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 20 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 21 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 22 is a cross-sectional view of a lens employing a microlens arrayaccording to one embodiment of the present invention.

FIG. 23 is a chart showing measured properties of a lens employing amicrolens array according to one embodiment of the present invention.

FIG. 24 is a chart showing measured properties of a lens employing amicrolens array according to one embodiment of the present invention.

FIG. 25 is a chart showing measured properties of a lens employing amicrolens array according to one embodiment of the present invention.

FIG. 26 is a chart showing measured properties of a lens employing amicrolens array according to one embodiment of the present invention.

DETAILED DESCRIPTION

Specific embodiments of the invention will now be described withreference to the accompanying drawings. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art. Theterminology used in the detailed description of the embodimentsillustrated in the accompanying drawings is not intended to be limitingof the invention. In the drawings, like numbers refer to like elements.

The present invention provides ophthalmic lenses, lens designs, andmethods for manufacturing ophthalmic lenses that achieve relatively thinsingle vision prescription clear lenses and sunglasses manufactured forany desired prescription. The present invention also provides ophthalmiclenses, lens designs, and methods for manufacturing ophthalmic lensesthat achieve multifocal lenses that have relatively large opticallyfunctional portions for the different lens powers. These objectives areachieved, in part, by providing ophthalmic lenses employing an array ofmicrolenses formed thereon or therein. The individual microlenses of thearray of microlenses function as microprisms that refract light byhaving front and back surfaces oriented in different directions and/orby having different refractive indices. Accordingly, the individualmicrolenses of the array of microlenses may have the same or distinctoptical powers.

With reference to FIGS. 1-3 , a lens 10 according to the presentinvention employs a base lens 12 and a microlens array 14 formed on afront side or front optical surface 16 of the lens 10; formed on a backside or back optical surface 18 of lens 10; or formed on the frontoptical surface 16 and the back optical surface 18 of lens 10. Themicrolens array 14 is formed of a plurality of individual microlenses20. The lens 10 may, but need not necessarily, employ an optical power,i.e. the front side 16 and the back side 18 of the lens 10 may havedifferent base curves, as shown in FIG. 8 .

For the sake of clarity and explanation and with reference to FIG. 4 ,the base curve of the front optical surface 16 and the base curve of theback optical surface 18 of the lens 10 that contains the geometriccenter of certain of the microlens 20 of array 14 is referred to as the“low-frequency” curvature 26 of the surface of the lens 10. The localcurvature of the optical surface 22 of each microlens 20 is referred toas the “effective curvature” of the lens 10.

The individual microlenses 20 of a single array 14 are formed of asingle material, as shown in FIG. 5 , or, alternatively, are formed oftwo or more different materials, as shown in FIG. 6 . Alternativelystated, the individual microlenses 20 may have a homogenous compositionor may have a heterogeneous composition. In the case of microlenses 20having a heterogeneous composition, layers 21 a, 21 b . . . 21 n, of thedifferent materials may be stacked upon one another so as to form amultilayered microlens 20 when viewed in elevation or viewedsubstantially parallel to the surfaces 16 and/or 18 of lens 10. WhileFIG. 6 shows the layers 21 a, 21 b . . . 21 n, oriented in a planeparallel to the front side 16 of the lens base 12, it will be understoodthat the orientation of the layers 21 a, 21 b . . . 21 n can vary, inpart, due to the desired manufacturing method and the desired refractionof the microlens 20.

The microlenses 20 of the microlens array 14 of the present inventionmay be formed of a variety of different materials depending on thedesired refractive index of the microlens and on the manufacturingprocess employed for formation of the array 14, base lens 12, and/orlens 10. For example, microlenses 20 of the microlens array 14 of thepresent invention may be formed of a bulk lens material, such aspolymeric resins suitable for injection molding, e.g. polycarbonate, ormonomers suitable for cast molding; a titanium oxide having a refractiveindex of approximately 1.9 to 2.3, e.g. titanium dioxide; a zirconiumoxide having a refractive index of approximately 1.88 to 2.1, e.g.zirconium dioxide; a tantalum oxide having a refractive index ofapproximately 2.07 e.g. tantalum pentoxide; a niobium oxide having arefractive index of approximately 2.1 to 2.35, e.g. niobium pentoxide;aluminum oxide having a refractive index of approximately 1.7 to 1.9;indium tin oxide having a refractive index of approximately 1.7 to 1.9;a tin oxide having a refractive index of approximately 1.9 to 2.0, e.g.tin dioxide; silicon oxynitride having a refractive index ofapproximately 1.5 to 2.0; and silicon nitride having a refractive indexof approximately 2; or combinations thereof.

The microlenses array 14 is formed, for example, of microlenses 20 thatare formed of a same material or materials, i.e. the microlenses 20 of asingle array 14 are formed of a homogeneous material or materials, or,alternatively, the microlenses 20 of a single array 14 are formed of aheterogeneous material or materials. For example, the individualmicrolenses 20 of a single array 14 may be formed of different materialshaving different refractive indices.

The microlens array 14 is formed, for example, of a same material fromwhich the base lens 12 is formed; of a material or materials that aredifferent or distinct from the material from which the base lens 12 isformed, or of a combination of a same material from which the base lens12 is formed and one or more materials that are different or distinctfrom the material from which the base lens 12 is formed. For example,the base lens 12 and some or all of the microlenses 20 of the array 14may be formed of different materials having different refractiveindices.

The individual microlenses 20 of the array 14 of the inventive lens 10are formed such that optical surfaces 22 of the individual microlenses20 have a substantially same geometry as one another, for example asshown in FIGS. 2-6 . Alternatively, the individual microlenses 20 of thearray 14 are formed such that the microlenses 20 within a single array14 have two or more substantially different or distinct geometries asone another. For example, as shown in FIG. 7 , the array 14 of the lens10 employs microlenses 20 a and 20 b having a first optical surfacegeometry 22 a and a second optical surface geometry 22 b, respectively.

FIG. 8 shows another example in which the array 14 of the lens 10employs microlenses 20 a and 20 c having a first optical surfacegeometry 22 a and a third optical surface geometry 22 c, respectively.The optical surface geometry 22 c of the microlenses 20 has an opticalsurface geometry that is different from the optical surface geometry 22a and that is substantially the same as the base curve of the frontsurface 16 of lens 10. Hence, the optical power of the microlenses 20employing the third optical surface geometry 22 c is a function of theoptical power of the base lens 12.

For the sake of clarity, it will be understood that the geometry of theoptical surface 22 of the microlens 20 may, but need not necessarily, bea property that primarily functions to define the optical power of themicrolens 20. For example, the optical power of the microlens may beprimarily defined by the refractive index from which the microlens 20 isformed rather than the geometry of the optical surface 22 of themicrolens 20. For example, the base lens 12 and some or all of themicrolenses 20 of the array 14 may be formed of different materialshaving different refractive indices.

As shown in FIGS. 9-11 , a shape of the individual microlenses 20 of thearray 14 when viewed in plan or perpendicular to the surfaces 16 and/or18 of lens 10, i.e. a shape defined by a periphery 24 of the microlens20, is for example rectangular, trapezoidal, regular polygonal, such ashexagonal, irregular polygonal, or any other shape. A single array 14may employ microlenses 20 having the same or different shapes defined bythe periphery 24 of the microlens 20. A maximum width, diameter, ordimension 30, shown in FIGS. 5 and 6 , of the shape defined by aperiphery 24 of the microlens 20 is in the range of approximately 0.001to 0.5 millimeters, for example 0.4 millimeters or 0.2 millimeters.

A cross-sectional shape of the individual microlenses 20 of the array 14when viewed in elevation or substantially parallel to the surfaces 16and/or 18 of lens 10 is, for example semi-circular, curved, rectangular,trapezoidal, regular polygonal, irregular polygonal, triangular,stepped, concaved, convexed, or any other shape, as shown in theaccompanying figures. A maximum thickness or dimension 32, shown inFIGS. 5 and 6 , of the cross-sectional shape of the individualmicrolenses 20 of the array 14 from the front surface 16 or back surface18 of the base lens 12 is, in part, dependent on the thickness of thebase lens 12 and the properties, for example the refractive index, ofthe material from which the microlens 20 is formed. The maximum heightor dimension 32 of the microlenses 20 may be in the range of 100angstroms to 0.1 millimeters.

In embodiments in which the microlenses 20 of array 14 are asymmetric inthe cross-sectional shape of the individual microlenses 20 of the array14 when viewed in elevation or substantially parallel to the surfaces 16and/or 18 of lens 10, the optical surface 22 may define a slope or angle34 relative to a plane of the front surface 16 or back surface 18 of thebase lens 12 or a tangent of the curvature of the front surface 16 orback surface 18 of the base lens 12. The optical surface 22 may define arelative sign 36 of the optical surface 22. For example, FIG. 5 shows anindividual microlens 20 having an optical surface 22 with a minus ornegative sign 36 a, and FIG. 6 shows an individual microlens 20 havingan optical surface 22 with a positive or plus sign 36 b. It will beunderstood by those skilled in the art that the sign of microlenses 20having the same cross-sectional shape when viewed in elevation orsubstantially parallel to the surfaces 16 and/or 18 of lens 10 will varydepending on the orientation of the asymmetry relative to the basecurvature of the lens.

In view of the above, it will be understood that the optical power of anindividual microlens 20 of an array 14 may be defined by one or acombination of the properties of the microlens 20 including, but notlimited to, the material employed to form the individual microlens 20,the geometry of the optical surface 22, the angle 34 of the opticalsurface 22, and the orientation of an asymmetry of the optical surface22.

A single array 14 according to the present invention can be formed ofindividual microlenses 20 that are the same or that vary in the shapedefined by the periphery 24 of the microlens 20; the maximum width,diameter, or dimension 30; the cross-sectional shape of the individualmicrolenses 20 of the array 14 when viewed in elevation or substantiallyparallel to the surfaces 16 and/or 18 of lens 10 is; the maximumthickness or dimension 32; the angle 34 of the optical surface 22;and/or in the sign 36 of the optical surface 22.

In embodiments in which the microlenses 20 of array 14 are asymmetric inthe shape defined by the periphery 24 of the microlens 20 and/or in thecross-sectional shape of the individual microlenses 20 of the array 14when viewed in elevation or substantially parallel to the surfaces 16and/or 18 of lens 10, such asymmetric microlenses 20 may be orienteduniformly throughout the array 14 relative to one another or may beoriented non-uniformly throughout the array 14 relative to one another.

In embodiments in which a single array 14 employs individual microlenses20 having different optical powers, for example, microlenses 20 a forfar vision; microlenses 20 b for intermediate vision; and/or microlenses20 c for near vision, may be uniformly distributed across the area ofthe array 14, as shown in FIG. 9 , or may be non-uniformly distributedacross the area of the array 14, as shown in FIG. 10 . Alternatively,the single array 14 employing individual microlenses 20 having differentoptical powers may have the form of concentric rings or ovals, as shownin FIG. 11 . For example, a multifocal lens having a prescription thatis plano for far vision, plus one diopter for intermediate vision, andplus two diopters for near vision may be desired. A low frequencycurvature of the front surface of the lens is plus four diopters.Accordingly, the effective curvature of the microlenses is plus fourdiopters, plus five diopters, and plus six diopters for the far,intermediate, and near vision, respectively.

The array 14 may cover, be formed over, or be incorporated through anentirety of the front side 16 and/or back side 18 of the lens 10, asshown in FIG. 12 . Alternatively, the array may be covered, be formedover, or incorporated through only a portion of the front side 16 and/orback side 18 of the lens 10 as shown in FIG. 13 . For example, as shownin FIG. 13 , the array 14 may be localized to only a lower or upperportion of the lens 10 such that the portion of the lens 10 notemploying array 14 provides a user with an optical power and the portionof the lens 10 employing the array 14 provides the user with one or moredifferent optical powers. Accordingly, in certain embodiments of thepresent invention the same optical effect as those of typical bifocal,trifocal, or executive trifocal lens is achieved. However, the presentinvention provides such without the sharp steps that are visible at amacro-scale in conventional multifocal lenses and with larger functionalareas of different optical powers. Furthermore occupational specificlenses may also be easily realized by the present invention.

For the sake of clarity, it will be understood that in the accompanyingfigures and drawings the features of the present invention, for examplethe base lens 12, the array 14, and the microlenses 20, are shown so asto facilitate understanding of the present invention and are not shownto scale generally or relative to one another.

In one embodiment according to the present invention, all of themicrolenses 20 of the array 14 of lens 10 are formed of individualmicrolenses 20 formed of the same material or materials and are formedso as to have substantially the same optical surface geometry. The array14 is formed uniformly over an entirety or a substantial entirety of thefront optical surface 16 of lens 10 and/or over an entirety orsubstantial entirety of the back optical surface 18 of lens 10. Thematerial from which the array 14 is formed may, but need notnecessarily, be the same materials from which the lens base 12 isformed. The lens 10 advantageously provides a relatively thin, singlefocal power lens, for example, a relatively thin single vision sunglasslens.

In the present embodiment in which a single vision prescription lens,e.g. a sunglass lens, is designed and manufactured according to thepresent invention, the lens 10 is, for example, manufactured with alow-frequency curvature 26 of plus seven diopters so as to fit properlyinto, for example, a wrap-around style sunglass lens frame. If thetarget prescription for the lens 10 is minus ten diopters, then eachmicrolens 20 of the array 14 of lens 10 is produce with a concaveeffective curvature, in this case, with minus three diopters, so as toachieve the target prescription. For the sake of clarity, this exampleemploys the thin lens formula approximation that ignores refractiveindex and lens thickness and approximates lens powers by adding thefront and back surface power. For example, minus 10 lens power equalsminus three plus minus seven. FIG. 14 shows a comparison of a typicalminus ten diopters lens, left, relative to a ten diopters lens 10according to the present invention, right. FIG. 15 shows the array 14 onthe front surface 16 of the lens 10 according to the present invention.

In a second example of the present embodiment, the lens 10 is, forexample, manufactured with a low-frequency curvature 26 of plus sevendiopters so as to fit properly into, for example, a wrap-around stylesunglass lens frame. If the target prescription for the lens 10 of thisexample is plus six diopters, then each microlens 20 of the array 14 oflens 10 is produce with an effective curvature of plus 13 diopters, soas to achieve the target prescription. Again, this example employs thethin lens formula approximation that ignores refractive index and lensthickness and approximates lens powers by adding the front and backsurface power. For example, plus six lens power equals the sum of plus13 lens power and minus seven. FIG. 16 shows a comparison of a typicalplus six diopters lens, left, relative to a six diopters lens 10according to the present invention, right. FIG. 17 shows the array 14 onthe front surface 16 of the lens 10 according to the present invention.For the sake of clarity, the individual microlenses 20 of the array 14shown in FIGS. 15 and 17 are shown as having a square shape with adiameter of approximately 0.4 millimeters. It will be understood bythose skilled in the art that the present embodiment is not limited toapplication in single vision ophthalmic sunglasses.

The lens 10 having array 14 of the present invention allows for thefabrication of single vision lenses having a low-frequency curvature 26formed with most any optical power that are thinner than is typicallypossible without resort to more costly high index lens materials.Accordingly, the present embodiment advantageously allows for increasedflexibility in choice of frame and prescription combinations (currentlylimited by curvature of lens), choice of thinner lenses in any frame,and optimization of appearance and safety functions.

In a another embodiment of the present invention, the microlenses 20 ofthe array 14 of the lens 10 are formed of individual microlenses 20formed of the same material or materials but that have two or moresubstantially different optical surface geometries. The array 14 isincorporated into or formed uniformly over a portion or over an entiretyof the front optical surface 16 of lens 10. Such a lens 10advantageously provides, in part, a multifocal lens, such as a bifocal,trifocal, or executive trifocal lens, with large functional areas ofdifferent optical powers while not exhibiting sharp steps that arevisible at a macro-scale.

For example, with reference to FIG. 7 , the array 14 of lens 10 mayemploy microlenses 20 a and 20 b that are formed of a same material ormaterials. However, the microlens 20 a has an optical surface geometry22 a that is different or distinct from the optical surface geometry 22b of the microlens 20 b. In this example of the present embodiment, thearray is formed over an entirety of the front side 16 of the lens 10.Hence, any difference in the materials employed to form base lens 12 andthe array 14 is not relevant to the optical powers of the microlenses 20a and 20 b relative to one another.

In a further embodiment according to the present invention, themicrolenses 20 of the array 14 of the lens 10 are formed of individualmicrolenses 20 formed so as to have substantially the same opticalsurface geometry but the individual microlenses 20 are formed fromdifferent or distinct materials. The array 14 is formed uniformly over aportion or over an entirety of front optical surface 16 of lens 10. Themicrolenses 20 formed of different materials of the array 14 may beuniformly distributed across the area of the array 14, as shown in FIG.9 , or may be non-uniformly distributed across the area of the array 14,as shown in FIG. 10 . Such a lens 10 advantageously provides amultifocal lens, such as a bifocal, trifocal, or executive trifocallens, with large functional areas of different optical powers while notexhibiting sharp steps that are visible at a macro-scale.

For example, with reference to FIG. 18 , a user may have a prescriptionhaving a sphere of plus four diopters and an addition of plus twodiopters. A lens 10 according to one embodiment of the present inventionfor this user may have a distant portion employing microlenses 20 dformed of a material having a refractive index of 1.530 with a frontside 16 low frequency curvature 26 of plus six diopters and a back side18 low frequency curvature 26 of minus two diopters, such as that shownin FIG. 2 . For the power addition portion of the lens 10, the lens 10may employ microlenses 20 e formed of a material having a refractiveindex of 1.795 with a front side 16 low frequency curvature 26 of plussix diopters and a back side 18 low frequency curvature 26 of minus twodiopters. In this example of the present embodiment, the base lens 12 isa plano power thin lens with a front curve of plus two diopters and aback curve of minus two diopters. The different microlenses 20 d of thedistant portion and the microlenses 20 e of the power addition of thearray 14 may be arranged or grouped as shown in FIGS. 9-11 .

According to the above described example of the present embodiment, thetype of materials employed to form the individual microlenses 20 withinthe array 14 is varied between individual microlenses 20 of a singlearray 14 and the individual microlenses 20 are composed of only onematerial each. In other words, the material employed to form the array14 varies across the array 14, but the individual microlenses 20 of thearray 14 are each formed of only a single material. This example of thepresent embodiment is not limited to employing only two differentmaterials within or across the array 14. The array 14 may employ morethan two materials, for example, three different materials so as tocreate three unique optical powers.

In a second example of the present embodiment, in order to form thedesired multifocal lens of the present embodiment, the microlenses 20 ofarray 14 are formed of different materials across the thickness 32 ofthe microlens 20 and/or the base lens 12. A single or individualmicrolens 20 may be formed of one or more layers of different orheterogeneous materials as described with respect to FIG. 6 . Withreference to FIG. 19 , the array 14 of the lens 10 is formed ofmicrolenses 20 f and microlenses 20 g. The microlenses 20 g are definedor formed between the microlenses 20 f and/or by the absence of materialemployed to form microlenses 20 f employed over the surface 16 or 18 ofthe base lens 12. Hence, the optical power of microlenses 20 g areprimarily a function of the optical power of the base lens 12.

In this example, the base lens 12 is formed of a material having arefractive index of approximately 1.6. Hence, the microlenses 20 g ofthe array 14 are regarded as also being formed of a material having arefractive index of approximately 1.6. On the other hand, themicrolenses 20 f of the array 14 are formed of a material deposited uponthe surface 16 or 18 of the base lens 12 that has a refractive index of2.2 and of the base material having a refractive index of approximately1.6.

The different microlenses 20 d of the distant portion and themicrolenses 20 e of the power addition of the array 14 may be arrangedor grouped as shown in FIGS. 9-11. This example of the presentembodiment is not limited to employing only two different materialswithin or across the array 14 and is not limited to employing the shapedefined by a periphery 24 of the microlens 20 as shown FIGS. 9-11 . Thearray 14 may employ more than two materials, for example, threedifferent materials so as to create three unique optical powers.

In the above described examples of the present embodiment, it is notedthat the microlenses 20 d, 20 e, 20 f, and 20 g shown in FIGS. 18 and 19are formed such that the optical surfaces 22 of the individualmicrolenses 20 d, 20 e, 20 f, and 20 g have substantially the sameoptical surface geometry as one another. Asymmetries in the geometry ofthe optical surface, i.e. a prism angle, and the orientation of suchasymmetric individual microlenses 20 will depend both on the desiredoptical power of the individual microlens 20, as well as on the locationof the microlens 20 within the array 14 and on the lens 10. The opticalpower of the individual microlenses 20 d, 20 e, 20 f, and 20 g isdefined by the refractive index of the material employed to form theindividual microlenses 20 d, 20 e, 20 f, and 20 g and the prism angleand orientation of the surface 22, such as shown in FIGS. 5 and 6 . Thepresent embodiment provides multifocal power lenses that have asubstantially constant front and back low frequency curvature 26 overthe entire front side 16 and back side 18 of the lens 10.

In yet another embodiment according to the present invention, themicrolenses 20 of the array 14 of lens 10 are formed of individualmicrolenses 20 formed from different or distinct materials and areformed so as to have two or more substantially different optical surfacegeometries. The array 14 is formed uniformly over a portion or over anentirety of the front optical surface 16 of lens 10. Such a lens 10advantageously provides a multifocal lens, such as a bifocal, trifocal,or executive trifocal lens, with large functional areas of differentoptical powers while not exhibiting sharp steps that are visible at amacro-scale.

For example, with reference to FIG. 8 , the array 14 is formed of amaterial or materials that are different or distinct from the materialfrom which the base lens 12 is formed and the microlenses 20 of thearray 14 are formed such that the optical surfaces 22 a and 22 c of theindividual microlenses 20 a and 20 c have two or more substantiallydifferent or distinct geometries. As shown in FIG. 8 , the microlenses20 c are defined or formed between the microlenses 20 a and by theabsence of material employed to form microlenses 20 a employed over thesurface 16 of the base lens 12. Hence, the optical power of microlenses20 c is primarily a function of the optical power of the base lens 12.

In this example of the present embodiment, the array is formed over anentirety of the front side 16 and/or the back side 18 of the lens 10.The different microlenses 20 a and the microlenses 20 c of the array 14may be arranged or grouped as shown in FIGS. 9-11 . The presentembodiment provides multifocal power lenses that have a substantiallyconstant front and back low frequency curvature 26 over the entire frontside 16 and back side 18 of the lens 10.

In a second example of the present embodiment, the array 14 of lens 10is formed substantially the same as that described in theabove-described first example of the present embodiment. However, asshown in FIG. 20 , the asymmetries of the cross-sectional shape of theindividual microlenses 20 a of the array 14 having the same opticalsurface geometries when viewed in elevation or substantially parallel tothe surfaces 16 and/or 18 of lens 10 are oriented across the array 14 indifferent or opposing orientations. In this example, the base lens 12 isformed plano. Hence, the optical power of the microlenses 20 c is zerowhile the optical power of the microlenses 20 a is, for example plus twodiopters.

In this example of the present embodiment, the array is formed over anentirety of the front side 16 and/or back side 18 of the lens 10. Thedifferent microlenses 20 a and the microlenses 20 c of the array 14 maybe arranged or grouped as shown in FIGS. 9-11 . The present embodimentprovides multifocal power lenses that have a substantially constantfront and back low frequency curvature 26 over the entire front side 16and back side 18 of the lens 10.

In a third example of the present embodiment, in order to form thedesired multifocal lens of the present embodiment, the microlenses 20 ofarray 14 are formed of different materials across the thickness 32 ofthe microlens 20 and/or the base lens 12; are formed so as to have twodifferent optical surface geometries; and the asymmetries of thecross-sectional shape of the individual microlenses 20 of the array 14having the same optical surface geometries when viewed in elevation orsubstantially parallel to the surfaces 16 and/or 18 of lens 10 areoriented across the array 14 in different or opposing orientations. Asingle or individual microlens 20 may be formed of one or more layers ofthe different or heterogeneous materials as described with respect toFIG. 6 . With reference to FIG. 21 , the array 14 of the lens 10 isformed of microlenses 20 a 1 having a minus sign 36; microlenses 20 a 2having a plus sign 36; and microlenses 20 c. The microlenses 20 c aredefined or formed between certain of the microlenses 20 a 1 and 20 a 2and/or by the absence of material employed to form microlenses 20 cemployed over the surface 16 or 18 of the base lens 12.

In this example, the base lens 12 is formed plano. Hence, the opticalpower of the microlenses 20 a 1 is minus one diopter. The optical powerof the microlenses 20 a 2 is plus one diopter, and the optical power ofthe microlenses 20 c is zero diopter, as indicated in the right side ofFIG. 20 .

In a fourth example of the present embodiment, the array 14 of lens 10is formed substantially identical as that described in the above-secondexample of the present embodiment. However, the base lens 12 is formedwith a power of plus four diopters. Hence, the optical power of themicrolenses 20 a 1 is plus three diopters. The optical power of themicrolenses 20 a 2 is plus 5 diopters, and the optical power of themicrolenses 20 c is plus four diopters, as indicated in the right sideof FIG. 22 .

In the third and fourth examples of the present embodiment, the array isformed over an entirety of the front side 16 and/or back side 18 of thelens 10. The different microlenses 20 of the array 14 may be arranged orgrouped as, for example, shown in FIGS. 9-11 . The present embodimentprovides multifocal power lenses that have a substantially constantfront and back low frequency curvature 26 over the entire front side 16and back side 18 of the lens 10.

By way of comparison, the array 14 of the third and fourth examples ofthe present embodiment may in certain situations provide advantages overthe array 14 of the second example of the present embodiment describedabove and shown in FIG. 20 . For example, the back-to-back or opposingsign 36 configuration of the adjacent microlenses 20 a 1 and 20 a 2allows for increased differentials of optical powers of adjacentmicrolenses 20 while employing decreased maximum thickness or dimensions32 of the respective microlenses 20 relative to the array 14 of thesecond example of the present embodiment. In other words, in order forthe array 14 of the second example to achieve, for example, a plus twodiopter differential between adjacent microlenses 20 a and 20 c, withoutincreasing a maximum width or dimension 30, of the shape defined by aperiphery 24 of the microlens 20 a, the microlenses 20 a must have anincreased maximum thickness or dimension 32 and an increased angle 34 ofthe respective microlenses 20 a relative to the microlenses 20 a 1 and20 a 2 of the third and fourth examples.

In certain embodiments of the present invention, the microlenses 20 ofthe array 14 are formed on the front surface 16 and/or the back surface18 of the base lens 12 by what is referred to as subtractive methods.For example, the microlenses 20 of the array 14 are formed on the frontsurface 16 and/or the back surface 18 of the base lens 12 by the directmachining or mechanical etching of the front surface 16 and/or the backsurface 18 of the base lens 12.

In certain embodiments, the formation of the microlenses 20 of the array14 by the direct machining or mechanical etching of the front surface 16and/or the back surface 18 of the base lens 12 is employed with laminatebase lenses formed of two or more base materials having differentrefractive indices. For example, the front surface 16 of the base lens12 is formed of a relatively thin layer of a high index polymericmaterial and the back surface is formed with a thicker layer of a lowerindex material. During the direct machining or etching of the frontsurface 16, certain of the microlenses 20 of the array 14 are formed byremoval of a portion or an entire thickness of the relatively thin layerof a high index polymeric material. Other of the microlenses 20 of thearray 14 are formed by the portions of the high index polymeric materialthat are not machined or mechanically etched from the front surface 16of the base lens 12.

Alternatively, in certain embodiments of the present invention, themicrolenses 20 of the array 14 are formed on the front surface 16 and/orthe back surface 18 of the base lens 12 by direct machining ormechanical etching of the molding surfaces that form the front surface16 and/or the back surface 18 of the base lens 12. Such molding surfacesinclude injection molding surfaces and cast molding surfaces. Aftermolding, the lens 10 is removed from the lens mold with the array 14molded directly in or on the front surface 16 and/or the back surface 18of the lens 10.

In certain embodiments of the present invention, the microlenses 20 ofthe array 14 are formed on the front surface 16 and/or the back surface18 of the base lens 12 by what is referred to as additive methods. Forexample, the microlenses 20 of the array 14 are formed on the frontsurface 16 and/or the back surface 18 of the base lens 12 by the directaddition of a same material as employed to form the base lens 12; theaddition of a different material than employed to form the base lens 12on to the front surface 16 and/or the back surface 18 of the base lens12; or a combination thereof.

In certain embodiments of the present invention, the microlenses 20 ofthe array 14 are formed on the front surface 16 and/or the back surface18 of the base lens 12 by vapor deposition processes, such as chemicalor physical vapor deposition. For example, in one experiment, arrays ofmicrolens having diopters in the range of one to two were fabricated ona front surface of finished, single vision lenses having a plano power.The arrays were produced by placing wire screens having either squared,rectangular, or diamond shaped openings with a maximum dimension ofapproximately 0.50 to 1.00 millimeters on an optical surface of eachlens. The masked lenses were subjected to sputter deposition ofapproximately 10,495 angstroms of zirconium dioxide having an index ofrefraction of approximately 2.1. The thickness of the individualmicrolenses of the array was achieved using time and joules/second witha substrate at a constant revolving at approximately 100 revolutions perminute on a rotating carousel.

Local optical power readings were obtained across different regions ofthe arrays on the lenses produced. The resulting optical power readingsfor different microlenses ranged from zero to more than five diopterswith the variations between adjacent microlenses in the range of one tothree diopters. Multiple optical power readings for a single microlensshowed little variation, e.g. variations in the range of a fewhundredths of a diopter.

FIGS. 23-26 show optical data for an example lens formed as describedabove. More particularly, FIG. 23 shows sphere power readings of themicrolenses of the array on the lenses produced. The power readings aredistributed over a 15-by-15 grid that covers a 40-by-40 millimetersquare region of the lens, i.e. the step size between readings is about40/15=2.67 millimeters. However, the microlenses formed are less than 1millimeter in width. Hence, each power reading is the combined powerprovided by the cluster of microlenses enclosed by each of the 2.67millimeter width covered by each reading. The power readings are in therange of approximately zero to six diopters. At the center of the lens,the sphere power reading is 1.38 diopters, the adjacent power reading tothe right is 0.19 diopters, and the following power reading is 2.90diopters. These significant power jumps from one reading to the next areobserved across the entire region measured. The power jumps are a resultof the different powers of the microlens of the microlens array formed.Such power jumps would not be possible in a traditional orconventionally formed multifocal ophthalmic lens.

FIG. 25 shows sphere power readings of the same lens described withregard to FIG. 23 . The readings are shown in a three-dimensional plotin which the z-axis represents the sphere power. The significant powerjumps between adjacent regions result in a three-dimensional plot thathas the appearance of many stalactites and stalagmites clusteredtogether.

FIG. 24 shows cylinder axis power readings of the same lens describedwith regard to FIG. 23 . It is observed that the cylinder axis variessignificantly from one reading to the next across the entire region.

FIG. 26 shows cylinder power readings of the same lens described withregard to FIG. 23 in a three-dimensional plot in which the z-axisrepresents the cylinder power.

At a typical vertex distance of 11 to 15 millimeters in front of aviewer's eye, the viewer could resolve the optical power change on thelens surface of the lenses described above due to the presence of themicrolens.

In certain embodiments of the present invention, the microlenses 20 ofthe array 14 are formed on the front surface 16 and/or the back surface18 of the base lens 12 by a combination of the above describedsubtractive methods, a combination of the above described additivemethods, or combination of the above described additive methods andsubtractive methods.

In certain embodiments of the present invention, the microlenses 20 ofthe array 14 are formed on the front surface 16 and/or the back surface18 of the base lens 12 by photolithography, optical lithography, and/orultraviolet lithography known by those skilled in the art. One skilledin the art will recognized that depending upon the exact process of suchtechniques, the method can be considered additive, subtractive or acombination thereof. Such techniques allow for the control of theorientation of the surface of the microlenses 20 or the array 14 inorder to refract the principal light ray in the desired direction. Thephotoresist may be developed by a laser.

In certain embodiments of the present invention, the microlenses 20 ofthe array 14 are formed on a surface of the thin film or a surface of athin film laminate through any one of the herein described subtractivemethods, additive methods, or a combination thereof. The resulting thinfilm or thin film laminate having an array 14 formed thereon is thenincorporated into an ophthalmic lens through an insert or waferinjection molding process or through an insert or wafer cast moldingprocess. Exemplary insert or wafer injection molding processes aredescribed in the assignee's U.S. Pat. No. 5,757,459. Such thin film orthin film laminate may be formed of polycarbonate, polyethyleneterephthalate, polyvinyl alcohol or other suitable thin film. The thinfilm or thin film laminate may be incorporated into an interior of thebase lens 12 or on an optical surface 16 and/or 18 of the base lens 12.

The base lens 12 according to the present invention is, for example,formed of glass, crystalline quartz, fused silica, or soda-lime silicateglass. In certain embodiments of the present invention base lens 12 isformed of a plastic bulk material or resin suitable for cast orinjection molding. For example, such materials include polymers based onallyl diglycol carbonate monomers (such as CR-39 available from PPGIndustries, Inc. and SPECTRALITE and FINALITE Sola International Inc.)and polycarbonates (such as LEXAN available from General Electric Co.).

In certain embodiments of the present invention, the lens according tothe present invention may be transparent or may employ an active orstatic coloring substrate mixed directly into the bulk material orresin. Such optical articles may further employ additional functionalcharacteristics in the form of coatings, laminates, thin film inserts,and/or thin film laminates. The functional attributes of such films,laminates, or coatings may include, for example, coloration, tinting,hard coating, polarization, photochromism, electrochromism, UVabsorption, narrow band filtering, and easy-cleaning.

Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theclaimed invention. Accordingly, it is to be understood that the drawingsand descriptions herein are proffered by way of example to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

1-10. (canceled)
 11. A method for forming a spectacle lens comprising:providing a front mold surface that forms a front surface of a baselens; providing a back mold surface that forms a back surface of a baselens; forming microlenses on at least one of the front mold surface andthe back mold surface; molding the base lens between the front moldsurface and the back mold surface; and, thereby producing a base lenswith plurality of microlenses molded directly on at least one of thefront surface and the back surface of the base lens.
 12. The methodaccording to claim 11, wherein molding the base lens comprises castmolding the base lens.
 13. The method according to claim 11, whereinmolding the base lens comprises injection molding the base lens.
 14. Themethod according to claim 11, wherein the microlenses have the sameoptical surface geometry as one another.
 15. The method according toclaim 11, wherein the microlenses are formed uniformly over a portion orover an entirety of the front surface.
 16. The method according to claim11, wherein the base lens is formed to be a single vision lens with alow-frequency curve.
 17. The method according to 11, wherein themicrolenses are formed by direct machining.
 18. The method according toclaim 11, wherein the microlenses are formed by mechanical etching. 19.The method according to claim 11, wherein the microlenses are formed ina pattern of concentric rings.
 20. The method according to claim 11,wherein some of the microlenses have different power than othermicrolenses.